Method of making yarns, films, and the like and product thereof



Patented July 13, 1937 PATENT OFFICE v METHOD OF MAKING YARNS, FILMS, AND

THE LIKE AND PRODUCT THEREOF Camille Dreyfus, New York, N. Y., and William Whitehead, Cumberland, Md.,

assignors to Celanese Corporation of America, a corpora- I tion of Delaware No Drawing. Application October 22, 1929, Se-

rial'No. 401,625. Renewed January 22, 1937 4 Claims.

This invention relates to the manufacture of articles such' as yarns, films, etc., from solutions or plastic masses containing organic derivatives of cellulose such as'cellulose acetate.

An object of our invention is to render solutions'or plastic masses to be employed for making articles more fluid.

A further object of our invention is to produce artificial yarn or filaments of organic derivatives of cellulose of finer dimensions than has been heretofore possible. Other objects of our inventionwill appear from the following description.

In the manufacture of filaments, yarns, films, etc., from derivatives of cellulose, the same are dissolved in a suitable solvent to form a solution of desired concentration. In all cases, the solution thus formedis more or less viscous. For the ease of handling of such solutions it is desirable that for a given concentration, they should have minimum'viscosity.

We have found that if a relatively small amount of an electrolyte is incorporated in solutions or plasticmasses containing organic derivatives of cellulose, the viscosity of the same is materially reduced. This reduction of viscosity facilitates the filtering," conveying, and working of such solutiOnsand plastic masses.

In accordance with our invention we prepare solutions or plastic masses of reduced viscosity by dissolving an organic derivative of cellulose in a suitable solvent or solvent mixture while incorporating a suitable proportion of an electrolyte, The solutions or plastic masses thus formed may be used as such or may be formed into articles such as'filaments, yarns, photographic films an'd various articles. I

Any'suitable organic derivative of cellulose may be employed suchas organic esters of cellulose ,and cellulose ethersg. Examples of organic esters "of c-eImmseai-ecellulose acetate, cellulose formate, cellulose propionate and cellulose butyrate while examples of cellulose ethers are ethyl cellulose, methyl cellulose and benzyl cellulose.

The organic derivative of cellulose is dissolved in a suitable solvent or solvent mixture such as acetone, mixtures of ethylene dichloride and ethyl or methyl alcohol, mixtures of methylene chloride and ethyl or methyl alcohol, etc. If desired other and higher boiling solvents such as ethyllactate, diacetone alcohol, etc., may also be added to the solution, and in some cases plasticizers such as dibutyl tartrate or diethyl phthalate may be added to the solution.

As stated, in order to reduce the viscosity of the solution oi the derivative oi cellulose, a suitable proportion of an electrolyte is incorporated therein. The term electrolyte includes those substances which increase the electrical conductivity of the particular solvent to which it is added. Any suitable electrolyte may be employed in this invention, examples of which are aluminum chloride, aluminum sulphate, aluminum resinate, barium chloride, and various soaps such as copper oleate, magnesium oleate, zinc oleate and potassium ricinoleate. such as various acids may also be mentioned. We have found that salts of metals of high valence are preferable, the higher the valence of the metal, the more effective the salt of the same for this purpose. It is preferable to employ an electrolyte which does'not corrode the Other electrolytes metal of the apparatus in which the solution is" formed and handled. Thus if iron, steel or galvanized iron apparatus is employed, we prefer to employ salts of zinc, aluminum or other metals high in theelectromotive force series. One'or a mixture of two or more of the electrolytes maybe employed.

The proportion of the electrolyte added to or incorporated'in the solution of the derivative of cellulose is of utmost importance. We have found that generally the proportions may vary from 0.05 to, 4% of the weight of the organic derivative of cellulose present. If too large a proportion of the electrolyte is employed, the same tends to precipitate or coagulate the derivative of cellulose from the solution. I

By the addition of the electrolyte in the manner desired, the viscosity of the solution formed is reduced considerably. Because of this reduction in viscosity, the solutions may be filtered more readily and economically and when ex-' truded through fine orifices in the spinning of yarn do not tend to clog such orifices. Moreover pipes of smaller diameter may be employed reduced viscosity. Moreover by employing electrolytes in the manner described, more concentrated solutions of derivatives of cellulose may be made and which have the same viscosity as solutions containing smaller amounts of derivatives of cellulose and no electrolyte.

This invention lends itself to many applications. Thus in the making of lacquers, dopes, varnishes, etc., containing the organic derivative of cellulose and the other constitutents normally employed such as volatile, medium and high boiling solvents, plasticizers, resins and pigments, by the addition of the small amount of the electrolyte, the viscosity is reduced. This reduction 40 for conveying such solutions because of their in viscosity renders the application of such lacquers by brushing or spraying much easier, and permits, if desired, the use of a lacquer containing a much larger preponderance of derivative of cellulose.

If solutions containing organic derivatives of cellulose and electrolytes are extruded through orifices of a spinneret into a drying atmosphere or into a precipitating bath, many advantages result. Filaments of much finer denier than have heretofore been possible may be made. We have found that in some cases, filaments may be spun from solutions containing the small amount of electrolyte, which have a denier of or less of that of the finest filaments that can be made from like solutions not containing the electrolyte.

Yarn or filaments made from solutions containing certain electrolytes delustre more readily in hot or boiling water or aqueous solutions than yarn made in the old manner. Moreover yarns or filaments made in accordance with this invention often have greater pliability and may be knitted more closely than former yarns, especially in those cases where electrolytes containing higher fatty acid radicals are used. I

In the making of plastic compositions, our invention may be utilized to reduce the amount of volatile solvents employed to make a composition of such consistency that it may be worked. This reduction of the volatile solvent content is of great importance, since the time required for seasoning articles, particularly relatively thick sheets, blocks, tubes and the like, to remove residual volatile solvent is materially reduced.

In order further to illustrate our invention but without being limited thereto, the following specific examples are given.

Example I A spinning solution is made by dissolving 25' parts by weight of an acetone soluble cellulose acetate in 71 parts of acetone and 4 parts of water, which water contains '7 grams of aluminum sulphate per litre. The solution thus formed has a viscosity approximately lower than a solution prepared with all the above ingredients except the aluminum sulphate.

The solution thus formed is extruded through orifices into a drying evaporative atmosphere and the filaments thus formed may be drawn out into filaments of from 15 to finer size than may be obtained from a similar solution that does not contain the aluminum sulphate.

Earample II tone and 4 parts of water, there is added a cop-,

per soap, such as copper oleate, in amounts equal to 2% of the weight of the cellulose acetate. :Re-

sults similar to that obtained in Example I are attained.

' removes the copper.

Filaments may be spun from such solution, which filaments are of finer size than can be spun from a similar solution not containing the copper oleate. Yarns formed from this solution are more pliable than are yarns formed from similar solutions not containing the copper oleate, and such yarn may be formed into a more closely knitted fabric.

I 'If the faint green color imparted by the copper oleate to the yarn is objectionable, this may be removed by scouring, preferably in an acid bath, containing 0.1% of hydrochloric acid which Example III The process of Example II is repeated, substituting zinc oleate for the copper oleate. Similar results are obtained.

The use of zinc oleate or other zinc salts is particularly recommended in those cases where iron or galvanized iron vessels or apparatus are employed, since the zinc salts cause no corrosion of the apparatus.

Aluminum resinate, potassium ricinoleate or other soapsv or metallic salts may be substituted for the electrolytes in the above examples with similar results.

It is to be understood that the foregoing detailed description is given merely by way of illustration, and that many variations may be made therein without departing from the spirit of our invention.

Having described ourinvention, what we claim and desire to secure by Letters Patent is:

l. Yarns made from a solution containing cellulose acetate and copper oleate in amount equal to 0.05 to,4% of the cellulose acetate present. I

2. In the manufacture of filaments, yarns and the like by the extrusion of solutions of cellulose acetate into a setting medium,, the step which comprises incorporating into the said solutions copper oleate in amounts equal to 0.05 to 4% of the c-ellulose acetate present.

3. Yarns made from a solution containing derivatives of cellulose selected from the group consisting of organic acid esters of cellulose and cellulose ethers and copper oleate in amount equal to 0.05 to 4% of the derivative of cellulose present. o

4. In the manufacture of filaments, yarns and the like'by the extrusion of solutions of derivatives of cellulose selected from the group consisting of organic acid esters of cellulose and cellulose'ethers into a setting medium, the step which comprises incorporating into the said derivative of cellulose copper oleate in amounts equal to 0.05 to 51% of the derivative of cellulose present.

CAMILLE DREYFUS. WILLIAM WHI'I EHEAD. 

